Skyline 50k Endurance Run

AUG
2
2026
A classic trail event in Castro Valley offering 50K and 21K loop courses through East Bay Regional Parks, with on-course aid stations, volunteer support, race swag, and age-group awards.
Sun 2 Aug 2026
50 kilometers Half Marathon

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Skyline 50k Endurance Run

Skyline 50k Endurance Run is a trail event in Castro Valley, California, with races over a loop course that starts and finishes at Lake Chabot Marina and travels through East Bay Regional Parks to Skyline Gate. The event offers the following distances:

  • 50K
  • 21K

The race is one of the oldest continuously running 50k events in the United States and has been selected as an OG Ultra by Ultrarunning Magazine. Course materials and navigation files are provided, including athlete guides and GPX downloads for both the 50k and the half marathon.

Organizers publish a pre-race digital briefing and a bib pickup option the day before the race at Sports Basement Berkeley. On-course support includes staffed aid stations run by local Bay Area running groups and a Volunteer Safety Patrol positioned at key intersections. Past finishes at Chabot Marina have included post-race food and beverage service.

All entrants receive a race shirt, Skyline socks, and a finisher medal. Awards are given to overall winners and three deep by age group. The event is part of the P-USATF Grand Prix and both races carry UTMB Index status. Registration policies note that refunds are not generally offered; deferrals are allowed outside of 30 days while no deferrals are offered within 30 days. Visit the organization's website for the most recent information.

50 km
50k
Half Marathon
21k
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